Belt



Jan. 8, 1946.

A. L. FREEDLANDER BELT 5 Sheets-Sheet 1 Filed lgpril 12, 1941 nwi/vrok ABRAHAM 4. mzmmwm ATTORNEYS Jan. 8, 1946.

A. L. FREEDLANDER BELT Filed April 12, 1941 3 Sheets-Sheet 2 INVEN'II'OQ ABRAHAM L. FQEEDLANDEQ' FIG-- 3 Ai-TQQNEYs Jan. 8, 1946.

A. L. FREEDLANDER BELT Filed April 12, 1941 3 Sheets-Sheet 3 FIE-J4 FIE'n' I5 BELT FiE'nI'? 79 Fire!!! BELT ABRAHAM L. FQEEomoEg Patented Jan. 8, 1946 UNITED STATES PATENT ()FFICE- BELT Abraham L. Freedlander, Dayton, Ohio,assignor to The Dayton Rubber Manufacturing Company, Dayton, Ohio, a corporation of Ohio Application April 12, 1941, Serial No. 388,212

3 Claims. (01. 74-234) This invention relates to improvements in belts and their method of manufacture.

The principal object of this invention is to provide a belt wherein the bottom edge portions along the sides of the belt are relieved, or pressed inward, to eliminate friction action at the lower exposed ends, of the belt wrapper against the pulley flanges tending to separate the rubberized fab- 1gigcflforming the cover shortening the life of the -Another object is to provide an improved wrapped belt wherein the end portions of the cover or wrapper are crimped together in the form of a groove to prevent scuffing or pushing apart of the fabric layers of the cover as the belt passes between the flanges of a pulley.

Another object is to make a wrapped cog belt wherein the cogs or toothed portions comprises either the outer or innerside of the belt and wherein the belt is molded so as to compress the exposed edges of the cover together along the sides of the belt body forming circumferential grooves producing a flexible belt having increased resistance to wear.

Another object is to provide an improved flext ible cog or plain belt wherein the cords form ing the neutral axis section of the belt are pro-- tected at the sides by one or more super-imposed plies of rubberized fabric. 1

It is another object to provide a wrapped cog belt having circumferential grooves molded in the belt along the inner bottom side edges which contract and firmly anchor the lower ends of the wrapper to the side walls of the belt.

Another object is to construct a 00g belt having a wrapper covering three sides of the belt which is molded so as to eliminate the corner or edges along the inner or bottom side portions whereby a belt of improved resistance to wear is Produced.

Another object is to construct belts of the molded cog, raw edge or plain type wherein the inner edge at opposite sides of the belt is eliminated forming a groove or depressed area which extends circumierentially of the belt whereby the belt is not subjected to excessive pressure at these edge portions during use. 'Another object is to provide an method of making a belt of the desired shape with or without cogs wherein the bottom side edges of the belt are compressed inward dun ing molding and curing of the belt producing an inwardly curved area extending circumferentially around'the inner side edges of the belt. In this way, the belt is shaped so that the lower exposed im proved edges of thebelt wrapper are not subjected to the rubbing action of the pulley during use.

Other objects and advantages will become apparent from the description given hereinafter taken in connection with the drawings, wherein Figure 1 illustrates diagrammatically in per spective the building up of the layers of belt material on a drum or mandrel in making the belt;

Figure 2 is an enlarged fragmentary sectional view through the built-up belt body, matrix and mandrel showing the different parts of the belt;

Figure 3 is a perspective view illustrating'the cutting of the built-up belt body into belts of the desired width and shape;

Figure 4 is a fragmentary detail sectional view showing the line or path of the knives in cutting out a V-type belt from the laminated material formed on the mandrel;

Figure 5 is a perspective view illustrating the method of applying a wrapper or cover around the outer surface and sides of the cut belts;

Figure 6 is a sectional .view taken through the built-up wrapped belt befor it is molded and vulcanized and showing the different layers making up the belt bo-dystl'llcture;

Figure 7 illustrates the step of vulcanizing the wrapped belts in a ring mold by placing the same in a curing oven or similar apparatus for heating the mold to the curing temperature;

Figure 8 is an enlarged detail fragmentary section taken. through the mold and belt body, substantially on line .88 of Figure 7, showing the corner beads and arched bottom wall cOnstruction of the ring moldfor shaping thebelt;

Figure 9 illustrates in perspective the method of removing the matrix from the inner surface ofbelt having cogs Figures 13 and 14 are similar views to Figures 11 and -1 2ill-ustrating a plain belt;

Figure '15 illustrates in perspective and cross section a modification of the cog belt shown in Figure 10 wherein beveled or diagonal portions are molded along th inner side bottom surface f As fllustrated in Figure 3, this of the belt'in placeof a groove or concave shaped area;

Figure 16 illustrates diagrammatically the method of molding a belt so as to provide an.

arched outer surface and depressed side bottom edges;

Figure 17 is a similar view as Figure 16 illustrating diagrammatically the method of molding a belt so as to have a concave outer surface;

Figure 18 illustratesanother modified form of 'a belt constructed so as to have fiat portions along the inner side adjacent the side edge grooves.

In general, belts heretofore made, particularly of the wrapped trapezoidal type which are designed to pass over pulleys having side flanges tend to flay away or separate the rubberized fabric layers of the cover along the bottom side edge portions due to the excessive pressure and friction to which the'belt is subjected along these edges. I have discovered that this .difiiculty can be avoided by molding the belt so as to'eliminate the corners along the side bottomportions of the belt. Further, mymethod provides an improved way of making a wrapped cog belt so as to prevent interference between the edge of the bottom of the wrapper and the sides ofthe pulley whereby a long-wearing belt is produced. I r

' Referring to the drawings in detail, the method of making a wrapped cog belt is illustrated as a typical'example of my invention. It is to be After the belt is cut to the desired shape, a

understood, however, that my invention is adapted for making variousother types of belts, such as molded raw edge and plain belts, as well as the conventional cog belt having inner or outer cogs. 35

Further, difierent shaped belts, such as illustrated inFigures 13 to 18,may be made.

In Figures 1 to 10, the steps employed in the manufacture of a wrapped cog belt according to my invention are illustrated. The steps are asfollows: r

Step I V A matrix is first formed by laying a plastic rubber compositiompre'ferably Stiflex, over a plate 3 7 having a cog-likesurface and pressing the rubber between the corrugations to form a sheet of the desired thickness. This corrugated matrix sheet 20 is partially cured so as to retain its shape and then wound on' a mandrel 2| with the cog or corrugated surface portion on the outside, as shown in Figure 1. The circumference of the mandrel is somewhat less'than the inside length of the finished belt due to the matrix layer which is subsequently removed. After'placing the matrix layer on the mandrel the corrugated surface of the matrix is coated with material to prevent bonding with the overlaid belt body material in the usual manner. Over the matrix teeth portion is laid a base fabric layer 23. The body of the belt is built up, as shown in Figure 2, comprising the compression section which consists of Stiflex and then a neutral axis cord layer 21 embedded in a rubber cushion layer 29. This forms the body portion of 'the belt without'the wrapper. v

7 step II V step comprises cutting the built up belt body, shown in Figure 2, so as to provide a belt or ainumber of belts having the desired shape.

having inclined side walls, as shown at 3l in In this instance, the knives, such as shown at 30, are set at the proper angle and held in position to cut the belt body material J circumferentially, of the mandrel forming belts Figure 4, producing-a trapezoid shaped belt 32. During the cutting operation, the mandrel is suitably rotated as by a motor 33 and the cuttin knives moved thereagainst to cut through the belt material and matrix as illustrated by the lines 3! in Figure 4. After cutting the belts to the desired shape they are removed from the mandrel and are now ready to have th e outer wrapper appliedthereto. 7 i Step III wrapper 35 comprising one or more plies of bias laid rubberized fabric is wound around the endless belt body 36, as shown 'in Figure 5. The cover or wrapper 35 is folded over the inner bottom edges of'the belt, as shown at 31, and may be skived oiT to provide a smooth surface. When the desired number of plies of rubberized fabric is applied the wrapped belt body 38 is then ready for molding and vulcanizing. a V 1 7 Step IV 1 Ring molds 39 are provided for this purpose,

as shown in Figures 7 and 8, and the belts are placed in the molds which are closed and rag wrapped, as at 3%, to compress the'belt body 33 i may be press cured to form a similar shaped belt.

" After vulcanization of lthe'belt is completed the I ring mold is opened and the belt removed and the corrugated matrix sheet 28 is separated from the belt by cutting the wrapper 35 along the side wall portions, as shown at 53 in Figure 9, after which the matrix is pulled away and discarded.

Removal of the matrix leaves a corrugated or cog surface around the inner side of the belt, as

shown at 52 in Figures 9 and 10. Along the side edges of the wrapper 35 the f material is com pressed and molded forming a furrow or groove 5 oanized to the side walls of the cogs 52 forming an integral body. The molded belt is .thus shaped to prevent rubbing of the inner corner bottom side surfaces of the belt against the pulley causingseparation of the wrapperplies or layers flaying them apart necessitating repairing or replacing of the belt. 7

In Figures 11 and 12 a modified cog belt is illustrated wherein the cog surface is formed on the outside of the belt, as shown at 58. In this construction a wrapper 62 is applied around the bottom or inner side surface of the belt, and ex-- tends upward over the sides and is vulcanized to the outer ends of the cogs fill. A groove or relieved area is molded along the bottom side surfaces of the belt body, as shown at 55,similarly as in the making of the inner cog belt illustrated in Figures 1 to 10. r

In the modification shown in Figuresl3 and 14, a plain belt is formed having a-fiat top surface t8 and relieved bottom corner surfaces 6 9.

In Figure 15' a plain inner cog raw edge belt;

7 This unites and firmly anchors the lower free ends 35a of the wrapper, as shown at 55, and the end portions of the wrapper are Vul-- is illustrated wherein the lower bottom side portions are molded to form a beveled or diagonal shaped section lying circumferentially of the belt body. This construction provides a belt which functions substantially as the circumferv entially grooved belts.

In Figure 16 there is illustrated a mold for forming belts having an arched or convex shaped outer surface, as shown at 12. In this instance, a filler 14 is applied over the outer side of the belt so as to mold it in the form of an arch. The bottom side grooves 16 are molded into the belt body similarly as in Figure 8.

In Figure 17 there is illustrated a similar ring mold wherein the filler 19 is shaped so as to mold the belt so that the outer surface is concave, as illustrated at 80, with the side grooves, similarly as in Figure 16.

In the modification shown in Figure 18 a wrapped belt is formed having a convex outer surface, as shown at B2, and flat portions 84 adjacent the grooved bottom side portions 86. The inner surface portion of the belt between the fiat portions is arched, as shown at 81. This construction provides a belt which is made in the same manner as described above but is merely a different shape.

It will be obvious that my invention is adapted in the manufacture of various types and shapes of belts.

The material of which the compressed section of the belt is formed which comprises "Stiflex is generally known in the art and comprises rubber reinforced with fine, parallel, textile fibers which are disposed transversely of the belt. The transverse reinforcements in the material greatly enhance the lateral incompressibility of the belt while providing good flexibility of the compression section about a transverse axis. The presence of these fibers in the material further substantially decreases the impact of the side surfaces of the belt against the driving pulley.

Bias-laid square woven rubberized textile fabric is used in the wrapper and cog covering portion of the belt which materially increases the tensile strength of the sections because the biaslaid textile threads limit the extensibility and strengthen the rubber section. The wrapper of the belt may comprise any number of plies as desired. In most instances four or five plies are used but this depends upon the conditions and uses to which the belt is to be subjected. The cord layer formin the neutral axis section is wound over a rubber cushion stock 29 which is placed on the rubber Stiflex compression section layer, as shown in Figure 2. The cords are embedded in the rubber cushion stock as shown having cogs transverse of its longitudinal axis and circumferential grooves along the inner side bottom edge portions, and webs forming a part of the side walls of the belt positioned between the circumferential grooves and the transverse (Dogs.

2. As an article of manufacture, a belt, the body of which includes rubber composition reinforced with parallelly laid fine textile fibers and reinforced cord and rubberized biasly square woven fabric layers forming a wrapper, said belt being molded to an integral endless body having alternate cogs and grooves transverse of its longitudinal axis and circumferential grooves formed around the inner bottom side portions thereof, and webs forming a part of the side walls of the belt positioned between the circumferential grooves and the transverse cogs and grooves.

3. An improved belt of the V-type having a body formed of rubberized composition including a layer of cords extending longitudinally thereof and having alternate cogs and grooves formed along the bottom circumferentially of the belt and transverse to the longitudinal axis thereof,

the bottom edges of said belt being shaped to form circumferential grooves, and webs forming a part of the side walls of the .belt positioned between the circumferential grooves and the transverse cogs and grooves,

ABRAHAM L. 

